When a resistor on a semiconductor substrate has a three-dimensional construction, a resistance length of the resistor becomes longer even if the resistor has a same occupation area compared with a conventional planar type resistor. Thus, the resistor having the three-dimensional construction has a large resistance compared with a conventional planar type resistor having a planar construction. For example, a poly-silicon thin film resistor can be formed easily by using a conventional silicon process, compared with a chrome-silicon alloy thin film resistor. However, the resistance of the poly-silicon thin film resistor is smaller than that of the Cr—Si alloy thin film resistor. Accordingly, when the poly-silicon thin film resistor has the three-dimensional construction, the poly-silicon thin film resistor has a small occupation area and a large resistance. Further, the poly-silicon thin film resistor can be formed with a low cost. Similarly, when a capacitor has a three-dimensional construction, an electrode area in the capacitor becomes large. Thus, the capacitance of the capacitor having the three-dimensional construction becomes large, compared with a conventional capacitor having a planar construction.
Thus, it is required for the capacitor and the resistor to have the three-dimensional construction so that the capacitor and the resistor have a large capacitance and a large resistance, and further, they have small occupation areas.
A semiconductor device having the above capacitor and/or the resistor having the three-dimensional construction is disclosed in, for example, JP-A-H07-122710, JP-A-2001-53250 and U.S. Pat. No. 6,689,696-B1.
In JP-A-H07-122710, a resistor is covered with an insulation film, and then, a groove is formed in a lateral direction by using a dry-etching method. After that, an etchant is poured into the groove, so that a cavity is formed. Further, the resistor having the three-dimensional construction is formed by using a substrate as a mold. Thus, a variation of impedance in the resistor in a micro-wave region is reduced.
In JP-A-2001-53250, a semiconductor device includes a first electrode having a three-dimensional construction, a second electrode facing the first electrode and a capacitor insulation film disposed between the first and second electrodes, which provide a capacitor for accumulating information. In this case, firstly, a poly silicon film having a rough surface is formed in a deep trench. Then, the capacitor insulation film composed of a silicon nitride film, and first and second tantalum oxide films is formed. Thus, even when the trench has high aspect ratio, the capacitor insulation film has excellent homogeneity.
U.S. Pat. No. 6,689,696-B1 discloses a method for manufacturing a semiconductor device having an insulation film and a three-dimensional conductive layer. In this case, the insulation film is deposited on a semiconductor substrate with changing deposition conditions so that an inherent etching rate of the film increases in a depth direction. Thus, the insulation film is selectively etched in order to form a through hole so that a storage electrode has a three-dimensional construction. Accordingly, the height of the storage electrode increases, and therefore, effective surface area becomes larger.
In the above devices, although the devices have the three-dimensional construction for providing a resistor or a capacitor, many complicated process for forming the three-dimensional construction in the devices are required.